1. Technical Field
The present invention relates generally to latching mechanisms for overhead doors, particularly for those overhead doors with a bifold construction.
2. Background Information
A typical overhead bifold door assembly, such as that described in U.S. Pat. No. 4,609,027, issued to Keller on Sep. 2, 1986, includes an upper door panel and a lower door panel, with the upper door panel hingedly connected to the lintel or header of the door frame. When in its first, closed position, the panels of the overhead door are vertically aligned and cooperate to close the doorway, while in its second, open position the panels of the overhead door are in a folded, generally horizontal, parallel relation. Generally, a door of the size contemplated by the present invention is movable by a winch mounted to the lower door panel, with the winch having a cable extending to a fixed location above the doorway for vertically raising and lowering the bottom edge of the lower door panel and bringing the overhead door to its closed position.
Various systems have been developed to address the need for a locking mechanism that will securely lock the panels in their closed, vertically aligned position. In the above-mentioned U.S. Pat. No. 4,609,027 issued to Keller, the weight of the motor and winch mounted on the lower door panel were relied on to act as an anchor to provide dead weight to help keep the door closed. However, such an arrangement would not necessarily provide the affirmative latching action desired to maintain securely the overhead door in its closed position.
An example of a latching system is disclosed in U.S. Pat. No. 4,903,747 issued to Johnson on Feb. 27, 1990. The system disclosed in this patent, however, is directed to a device usable with a pair of relatively small, vertically disposed left and right bifold door assemblies used as closet doors, window shutters, or the like, and cooperates with the inner panels of the two bifold door assemblies. Further, the system disclosed in this patent does not operate automatically as a part of the door opening and closing operation.
Another example of a latching mechanism is disclosed in U.S. Pat. No. 4,637,446 issued to McQueen et al. on Jan. 20, 1987, which shows a spring biased latching system. The system disclosed in this patent shows a latch member that engages a catchplate mounted on the door track. Opening and closing of the door is done manually, however, with a lift cable being used to disengage the latch member from the catchplate.
The automatic latching mechanism of the present invention overcomes the difficulties described above and affords other features and advantages heretofore not available.